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2007 C220 CDI Avantgarde W204
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68 Posts
Discussion Starter #1
Hi, C220 CDI W204.008 2007 135,000km, engine warning light On.
Checked with my MB2 iCarsoft diagnostic, first DTC is:

"The analogue/digital converter to the CDI control unit (N3/9) is faulty",

Have just driven 500 km for 35 l diesel, so 7 litres/100 km is nothing to worry about. User guide says to start worrying as I may damage the engine, but at least the consumption is OK. Question:
Does this error mean the engine is running on default values for injection volumes and other parameters? Anyone driven with the engine warning light on? How did you get that error fixed?

Would a Star diagnosis (cost: AUS$250) give me a print-out of possible problems and cost? Yes, but they like to fix it at $150/hr too.
It does not mean a new ECU as the car would have stopped, but it is still a worry. Taking the cover off from the ECU I noticed mechanics had already done the same thing as the plastic pin had been sheared off, which holds the cover to the ECU in place. Have they just wriggled the three contacts at the end of the three cables to the ECU to fix that same error?

Second error of 2054-007 is "Fuel temp sensor, open circuit or short" is easily tested via a multi meter before replacement, so that is no worry. From China that part A0009050800 is about US$20, the genuine from Merc is AUS$400. That part is below the fuel pump and you have to take the air intake hose off to get at it with a 19mm ring spanner.
 

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Registered
2007 C220 CDI Avantgarde W204
Joined
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68 Posts
Discussion Starter #2
Mercedes 2054-00 and 2054-007 Error (DTC) – Solved!

Interesting that the “Engine Fault” symbol appears just before a service and a few km afterwards, but then not anymore, so the software is setup to push you to the service!

2054-00 is “The AD converter of the control module N3/9 (CDI control unit) is faulty”. Had me worried as a new ECU costs heaps plus Merc has to copy the security (key) information from the dead unit’s ePROM into the new ECU or if you get a second-hand one, the security chip has to be un-soldered and soldered into the new (old) ECU. I also saw one of three plastic supports broken on the ECU, so a mechanic had already at least looked at the ECU? That message means the analogue/digital converter in the ECU is stuffed OR a sensor sending the signal to the ECU is stuffed.

My diagnostic displayed 1 of 2 and the second message was: “2054-007 Fuel temp. sensor open or short”. The forum tells me the resistance is supposed to be 3 kOhm. Rather than taking the fat air intake pipes off, measuring the resistance and then ordering a new fuel temp. sensor, I decided to order one and replace it regardless in one go.

A Merc. sensor is about AUS$400, one from Europe costs about 100 Euros and there are much cheaper ones available from China.

The location of the sensor is given on the forum with photos and a 19mm ring spanner is suggested to remove/install it, but that is not the best idea as there is no room. In my plumbing set I found a 19mm tube spanner.

My old temp. sensor was neither open or short, but displayed about 1.6 kOhm and that is strange, but I do not care as my diagnostic now for the engine management system tells me “No DTC” or no more errors and I am happy!
 
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